1. Field of the Invention
The present invention relates to a fan, and particularly to a fan with improved self-cooling capability.
2. Description of the Related Art
In a conventional fan, heat is generated by the internal components of the fan, such as the coils, in operation. Self-cooling heat dissipation is necessary to prevent the fan from overheating or being damaged due to the cumulative operation heat. However, the conventional fan self-cooling heat dissipation has drawbacks, as described hereafter.
FIG. 1(a), FIG. 1(b), FIG. 1(d), FIG. 1(e) and FIG. 1(c) illustrate an example of a conventional fan. FIG. 1(a) and FIG. 1(d) shows the exploded view, FIG. 1(b) and FIG. 1(e) shows the cross-sectional view, and FIG. 1(c) shows the top view of the conventional fan. The conventional fan has a frame 10, a stator 20, a magnetic ring 30, an iron case 50 and a rotor blade impeller 60.
The frame 10 has a base 11 in which the stator 20 is formed. The stator 20 has a plurality of coils 21 as shown in FIG. 1(b). The magnetic ring 30 is positioned around the stator 20. A cup-shaped iron case 50 is coupled to the magnetic ring 30, and the iron case 50 is provided with several heat dissipation holes 51 and several engaging holes 52 as shown in the enlarged illustration of FIG. 1(d). The heat dissipation holes 51 provided on the upper surface of the iron case 50 are positioned above the coils 21, and the engaging holes 52 are provided around the periphery of the heat dissipation holes 51. Further, the rotor blade impeller 60 is connected to the iron case 50, and an opening 65 is provided on the hub 61 of the rotor blade impeller 60 in order to expose the heat dissipation holes 51 to the environment.
Since the heat dissipation holes 51 are positioned above the coils 21 in the conventional fan, the coils 21 are exposed to the environment, as shown in the top view of FIG. 1(c). Thus, foreign matter such as dust or particles may directly fall onto the coils 21, diminishing the fan""s performance.
Thus, the present invention discloses a fan with improved self-cooling capability, in which foreign matter does not directly fall onto the coils of the fan.
The present invention discloses a fan with improved self-cooling capability including a frame, a stator, a magnetic ring, an iron case, and a rotor blade impeller. The frame is provided with a base and selectively formed with a plurality of guard blades. The stator is disposed on the base and provided with a plurality of coils and other components, such as a circuit board and electric components mounted on the circuit board, e.g. a driving IC and a Hall component.
The magnetic ring is magnetically coupled to the stator, which means the magnetic ring may be disposed substantially around the stator. The iron case is coupled to the magnetic ring and provided with at least a first heat dissipation hole. The rotor blade impeller has a hub, in which, in a first embodiment, at least a second heat dissipation hole aligned to the first heat dissipation hole is formed on the hub. In a second embodiment, an opening is formed on the hub and at least a heat dissipation notch aligned to the first heat dissipation hole is provided around the opening.
The rotor blade impeller is coupled to the iron case, in which the rotor blade impeller may be provided with at least an extrusion in order to couple to a part of the first heat dissipation hole of the iron case. In this case, it should be noted that the number of the first heat dissipation holes is greater than the number of extrusions.
In the present invention, the first heat dissipation hole and the second heat dissipation hole (or the heat dissipation notch) are not formed to directly alien to a position of the coils. For example, the first heat dissipation hole and the second heat dissipation hole can be formed above the magnetic ring; that is, the first heat dissipation hole and the second heat dissipation hole are not formed directly above the end of the coils. In this case, no part of the coils is directly exposed in the top view of the fan assembly, so that foreign matter does not directly fall onto the coils of the fan.
Further, the first heat dissipation hole and the second heat dissipation hole (or the heat dissipation notch) provide a heat exchange route to the outer environment, which provides for the desired self-cooling capability of the device by dissipating heat generated by the coils and other internal components. Thus, the fan of the present invention may be operated at a higher rotational speed and have a lengthened operation time.